1. Technical Field
The following description relates to a plasma generating apparatus. For example, the following description relates to a plasma generating apparatus including a first antenna part for generating plasma at an upper and central region of a substrate and a second antenna part for generating plasma at an upper and edge region of the substrate, and differently controlling the size of an electric current supplied to each antenna part and simultaneously, by differentiating an amount of gas supplied to the upper and central region and outer region of the substrate by means of a gas injection port formed at each antenna part, controlling a density of generated plasma depending on a position on the substrate and simultaneously controlling an etching characteristic and deposition characteristic of the substrate. The teachings herein may be variously applicable to semiconductor, Liquid Crystal Display (LCD), Organic Light-Emitting Diode (OLED), and solar cell processes and applicable to processing of materials applying plasma such as etching, Chemical Vapor Deposition (CVD), plasma doping, plasma cleaning, and the like.
2. Description of the Related Art
In general, plasma, an ionized gas, is the fourth state of matter that is not solid, liquid, and gas. Free electrons, positive ions, neutral atoms, and neutron molecules exist within plasma and incessantly interact with each other. The control of each component and concentration of free electrons, positive ions, neutral atoms, and neutron molecules is of significance. In engineering aspects, plasma is regarded as being in the field of gas, which can be formed and controlled by an external electric field.
The conventional plasma generating apparatus is described below.
FIG. 1 illustrates a plasma generating apparatus based on a Capacitively Coupled Plasma (CCP) scheme. The CCP plasma generating apparatus is constructed to generate plasma 18 based on capacitive coupling within a vacuum chamber 10, by installing two plate electrodes that are a source electrode 11 and an Electrostatic Chuck (ESC) (or a susceptor) 12 spaced a predetermined distance apart up/down within an upper and central region of a substrate 17, then placing the substrate 17 on a top surface of the ESC 12, and then applying a Radio Frequency (RF) power to the source electrode 11 and the ESC 12 from the external to form a strong electric field between the source electrode 11 and the ESC 12. Non-described reference numerals 13, 14, 15, and 16 denote a source RF power supply unit, a bias RF power supply unit, a source matcher, and a bias matcher, respectively. This conventional so-called CCP plasma generating apparatus can generate uniform plasma for a large scale target as well by using a plate capacitor.
FIGS. 2A to 2B illustrate a plasma generating apparatus based on an Inductively Coupled Plasma (ICP) scheme. The CCP plasma generating apparatus is constructed to generate plasma 28 based on inductive coupling, by placing a substrate 23 on a top surface of an ESC (or a susceptor) 22 within a vacuum chamber 21, applying a bias RF power to the ESC 22, and applying a source RF power to an antenna 26 disposed on a top surface of a ceramic vacuum plate 25 covering a top surface of the vacuum chamber 21 to induce a flow of an electric current, thus applying a magnetic field to the inside of the vacuum chamber 21 to form an inductive electric field by the applied magnetic field and accelerate electrons by the inductive electric field. Non-described reference numerals 24a and 27a denote a bias matcher and a source matcher, respectively. The conventional so-called ICP plasma generating apparatus can advantageously generate high density plasma compared to the CCP scheme. Also, the conventional so-called ICP plasma generating apparatus can generate high density plasma even at a low pressure of 10 mT or less at which the CCP scheme is impossible to do so and thus, is being widely used in a semiconductor process needing a low pressure characteristic.
Recently, semiconductor wafers have been large-sized to have a diameter of 300 mm beyond 200 mm and, from now on, are expected to be more large-sized to have a diameter of 450 mm. Particularly, in case of a large-size substrate, there is a need to differentiate densities of generated plasma from each other in an upper and central region of a substrate and an upper and edge region according to a process condition.
However, in case of the existing CCP scheme or ICP scheme, there is a problem that a density of plasma cannot be differently controlled depending on a position on the substrate.